SÃO PAULO—Anhui Jianghuai Automobile Co., the Chinese auto maker known as JAC, and its Brazilian partner said Friday that they decided to go ahead with plans to build a factory in Brazil on hopes that the government will modify a production tax.

SHC, the company that imports JAC automobiles into Brazil, said it would invest 80% of the 900 million Brazilian reals ($509 million) needed to build the factory, with JAC providing the rest. The factory will be built in the northeastern Brazilian state of Bahia, with output set to begin in 2014.

Brazil’s market—the world’s fourth-largest by sales—has attracted heavy investment. Sales are expected to grow 5% this year, slowing from last year’s 12% expansion as the government raised interest rates earlier this year to rein in an overheated economy.

The JAC factory, with initial capacity of 100,000 vehicles, will be in the city of Camacari, an industrial area where Ford Motor Co. has a plant. JAC will assemble and paint the cars locally, with stamping and motor-production capacity set to be built later.

JAC began selling cars in Brazil in March of this year, and through September had sold 17,421 vehicles. With four models sold locally, JAC accounts for 0.9% of all cars sold this year, according to auto dealers association Fenabrave.

SHC and JAC will also build a research center to locally develop parts such as flex-fuel engines–the predominant kind in Brazil, which can run on gasoline, ethanol, or a mixture of the two–as well as a design center and a test track.

The factory plans had been announced in August by SHC president Sergio Habib, although a location had yet to be decided upon. A month later, however, Brazil said it was raising the a tax on autos by 30 percentage points—to a range of 37% to 55%, from 7% to 25%—exempting only cars that used at least 65% locally produced content.

Mr. Habib said last month that the tax would also hurt auto makers that in recent months had begun building factories in Brazil, such as South Korea’s Hyundai Motor Co. and China’s Chery Automobile Co. Mr. Habib later said he may cancel plans to build the factory because it was impossible for any company to begin production with 65% local content.

Brazil’s Trade Ministry said earlier this week that it was considering making the rules more flexible. News reports said the government may consider gradually increasing local content requirements for newly installed factories.

Also Friday, Mr. Habib said Friday that he is in talks with India’s Tata Motors to import the company’s cars. Tata officials weren’t available to comment.